Re: Strange troubles with emulation

[Gary E. Miller]

Yo Владимир!

On Sun, 10 Jan 2021 20:03:07 +0300
Владимир Калачихин <v.kalachikhin@gmail.com> wrote:

> On Ubuntu 18.04
> gpsd: 3.17 (revision 3.17)
> 
> On Ubuntu 20.04
> gpsd: 3.20 (revision 3.20)
> 
> I tried to
> ? gpsfake -c 1 my_log.nmea
> 
> On Ubuntu 18.04 -- all right, works fine.

Actually, gpsd 3.17 is the broken one.

> On Ubuntu 20.04 -- cgps shows status NO FIX continuously, my own soft 
> receives "fix" and "no fix" status alternately: one second "fix",
> next second -- "no fix", next -- "fix"...

That is correct, and fixes a long standing gpsd bug.

The problem in 3.17 is that gpsd was not reporting "no fix" in many cases.
So when a GNSS receiver lost fix, that would not be reported to the client.

Pretty important when navigating a drone to know you fix is invalid!

> It happens with any log and with my own log player instead of gpsfake.

Good.

Many GNSS recivers will report "no fix", then "fix", in every cycle.  You
are just seeing what your receiver said.

> Where to dig?

Easy.  Look at your input file (log.nmea).  Then look at the gpsd
JSON output.  Compare the two and decide for yourself it the output
is what you would want from you input.


RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        gem@rellim.com  Tel:+1 541 382 8588

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